We all watch the nation's firefighters and recognize their courage but are they getting the help they need for one of the most dangerous jobs in america? Abc's chief investigative correspondent brian ross tonight on the men and women on the fire lines and whether someone is letting them down. Reporter: For the people who fight the increasingly frequent and deadly wild fires in this country, no sight is more welcome than the big air tankers that come in with thousands of gallons of chemical retardant aimed to slow down the spread of the flames. Drop right here. Reporter: But this summer in yarnell, arizona, with 20 hotshot firefighters battling an out of control blaze, officials asked urgently for six of the big tankers and none showed up. There was six air tankers ordered. Air tankers are a rare commodity in today's fire world. So you ordered six and you got none? We got one committed, but he didn't get here. Reporter: There simply were not enough planes to go around that day, the result of what an abc news investigation found has been a dramatic shrinking of the fleet from the 44 planes available just ten years ago. How many air tankers do you have available on any given day right now? Eleven. Reporter: That is a 75 percent cut in the fleet in just a decade. And most of those left are flying museum pieces, 50 years old or older. Including korean war vintage submarine chasers like this one. But it's no secret to the people responsible at the us forest service, which has been on notice since this 2002 report and eight others after it showing its large tanker fleet was badly aging and should be replaced. Forest service chief tom tidwell. What's been going on for the last 11 years? Well, we've been moving forward with using the aircraft that we had. Reporter: But officials in fire prone states say the depleted federal fleet puts lives at risk. In arizona, the 19 hotshots were trapped as the winds changed and the flames raced toward them. The situation's changed. We got some folks in trouble and I don't know where they're at yet. Reporter: All 19 died and fire officials told abc news even one of the large tankers might, might have made a difference. It may have bought them ten minutes to get to a little safer place than where they were. Could that have made a difference? Ten minutes could've. Absolutely. Reporter: The forest service says it has a plan for a brand new fleet of fire fighting aircraft but no one could come up with the money for what they say is an urgent need. Good to see you tonight. Thank you, brian.

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